Improvement in electro-magnets



T. A. EDiSGN,

Improvement in Elecro-Magnets.

Patented Aug. 27,1872.

INVENTOR kf/Jggl/ ATTY.

UNITED STATES PATENT OEEICE.

THOMAS A. EDISON, OF NEWARK, NEW JERSEY.

IMPROVEMENT IN ELECTRO-MAGNETS.

Specication forming part of Letters Patent No. 130,795, dated August 27,1872.

To all whom it may concern:

Be it known that I, THOMAS A. EDrsoN, of Newark, in the county of Essexand State of New Jersey, have invented an Improvement inElectro-Magnets; and the following is declared to be a correctdescription of the same.

If two magnets of equal power act in opposite directions and at thesaine distance from a swinging armature, said armature will not bemoved; but by removing one magnet further from the armature the otherwill be free to exert on that armature a force equal to the differencebetween the effective force of one magnet and the other. I avail of theforegoing features, and, instead of employing an adjustable spring todraw the armature back, I use a weight or spring of uniform power, and Iprovide a balancin g-pole energized by induced magnetism from the coreof the electro-magnet, and use an adjustment, so that the power of theelectro-magnet and the induced magnet are balanced in their action onthe armature; thus, when the electro-magnet is energized by a powerfulcurrent the induced magnetic pole will act with a proportionate power inthe opposite direction, or may be adjusted so as to leave onlysufficient surplus of force in the electro magnet to overcome the springor weight hence the armature will respond very rapidly, because theopposing forces neutralize each other instantly upon the circuit throughthe electro-magnet being broken.

In the drawing, Figure 1 is'a plan, and Fig. 2 is a side view, ofthisimprovement as applied to a relay-magnet.

The electro-magnet a is of usual character. The armature b is shown ason the swinging lever c that opens and closes the local circuit at d,and a spring or weight at e acts to draw back the armature. These partsare to be of any usual or desired character, according to the worlr forwhich the instrument is to be employed. The iron yokes h are connectedwit-h the cores i t of the electro-magnets, and they extend around tothe balancing-poles 7c k that pass through these yokes, and are made ofiron, and hence are magnetized with the same polarity as the cores t' 'iby induction. These poles k are to be adjusted to stand at the properdistance from the back of the armature, and for this purpose anysuitable means may be employedsuch as the cross-bar l and screw 'mwhiclimust not be of iron, or the proper polarity of the poles k would beinterfered with.

Itwill be apparent that the attraction of the poles k is acting up thearmature b in the opposite direction to that of the cores i, hence thatthe relative dista-nce of the poles from the armature must be such thatthe proper force will be exerted to move the armature when theelectro-magnet is energized. If the current is powerful the poles kshould be closer to the armature, and if feeble the poles should befurther removed.

I claim as my invention- The balancing-poles k, energized by inducedmagnetism from the cores t' of the electro-1nagnet, and acting inopposite direction to such electro magnet, substantially as set forth.

Signed by me this 9th day of May, 1872.

T. A. EDISON.

Witnesses GEO. T. PINCKNEY, OHAs. H. SMITH.

